Maternal hormones

Fleming, A.S., Cheung, U., Myhal, N., and Kessler, Z. (1989) Effects of maternal hormones on timidity and attraction to pup-related odors in female rats. Physiol Behav 46 449-453. 

Iodine and thyroid hormones affect all stages of human development, from in utero life to adulthood. Iodine deficiency leads to insufficient production of thyroid hormones, which play a vital role in the process of early growth and development of many organs. During pregnancy, both maternal and fetal thyroid hormones are required for normal fetal brain development. Of them, maternal hormones constitute the main source in the first and the second trimesters, whereas the contribution of fetal hormones becomes more important in the third trimester (de Escobar et aL, 1985 Vulsma et ai, 1989). Many studies indicate that iodine deficiency and iodine-induced maternal-fetal hypothyroxinemia result in impairment of central nervous system (CNS) development during fetal and early postnatal life. 

Therefore, based on the above Hmited evidence, we conclude that excess iodine exposure may influence maternal-fetal TH metabohsm by three mechanisms (1) excess iodine affects the maternal hormone thyroid level by inhibition of thyroid function and/or Dl activity (2) excess iodine has an effect on maternal—fetal TH transfer by affecting placental D2 and D3 activity and (3) excess iodine transferred by the placenta has a direct inhibition on the development and function of the fetal thyroid gland (Figure 88.2). 

CONTRIBUTION OF MATERNAL HORMONES AFTER ONSET OF FETAL THYROID FUNCTION. 

The presence of small ovarian follicular cysts is a normal ultrasound finding whatever the age. In neonates cysts may be found to be rather prominent due to maternal hormonal stimulation. 

Due to improvements in anesthesia and postoperative care, surgical correction of the exstrophied bladder and osteotomies can be done safely within the neonatal period. Since newborns are under the influence of the maternal hormone of Relaxin, bladder closure within 72 h of life is performed. At this age, there is a good chance of achieving pelvic closure without osteotomies in some patients. 

AVP plays a central role in water homeostasis of terrestrial mammals, leading to water conservation by the kidney. OT is primarily involved in milk ejection, parturition and in sexual and maternal behaviour. Both hormones are pqDtides secreted by the neurohypophysis, and both act also as neurotransmitters in the central nervous system (CNS). The major hormonal targets for AVP are the renal tubules and vascular myocytes. The hormonal targets for OT are the myoepithelial cells... 

Griffith M. and Williams G. (1996). Roles of maternal vision and olfaction in suckling-mediated inhibition of luteinizing hormone secretion, expression of maternal selectivity, and lactational performance of beef cows. Biol Reprod 54, 761-768. 

In addition to the classical stress hormones already reviewed, several other hormones are augmented in response to stress. Stress-induced prolactin release is one of the most frequently studied examples. There is no doubt about the causal relationship between stress and increased pituitary prolactin release, but the biological meaning is much less clear (G2). This phylogenetically old hormone has been shown to have more than 85 different functions in all vertebrate species. However, besides its role in the induction of maternal lactogenesis, the physiological importance of prolactin is at present not fully established. Experimental and clinical evidence supports the view that prolactin is also an immunoregulating hormone (M44, R18). Prolactin receptors are present on human T and B lymphocytes (R18), and T lymphocytes depend on prolactin for maintenance of immunocompetence (B19). In addition, it has been shown that prolactin is able to influence the devel-... 

Reproductive Effects. There is sufficient qualitative evidence to support the conclusion that at high occupational exposure levels lead has significant adverse effects on human reproduction, including increased incidences of spontaneous abortion, miscarriages, and stillbirths. The mechanisms responsible for these effects are unknown at this time, but many factors may contribute to these results. These factors include indirect effects of lead on maternal nutrition or hormonal status before and during pregnancy to... 

Stressful early life events, involving abuse or neglect, can have a life-long influence on the stress response, and lead to elevated levels of allostatic load for the lifespan. Overactivity of the stress hormone axis has been linked to prenatal stress or poor maternal care in rodent models, and this overactivity contributes to increased rates of brain and body aging [39]. 

Fleming, A. S. (1990). Hormonal and experiential correlates of maternal responsiveness in human mothers. In N.A. Krasnegor, and R.S. Bridges (Eds.), Mammalian Parenting Biochemical, Neurobiological and Behavioral determinants. Oxford University Press, New York, pp 184-208. 

Mulay, S., Varma, D.R. and Solomon, S. (1982). Influence of protein deficiency in rats on hormonal status and cytoplasmic glucocorticoid receptors in maternal and fetal tissues. J. Endocrinol. 95 49-58. 

In humans, studies of hormone and behavior interactions affecting maternal behavior have been limited to correlations between endogenous hormones and a variety of behavioral events normally associated with childbirth. Individual differences, of largely unknown origins, have a major impact on human parental behavior. In addition, child rearing experience is a powerful positive determinant of maternal responsivity, and the social environment, including the presence of supportive companions, can affect subsequent mother-infant interactions (Sosa, et al., 1980). 

Because oxytocin is a uniquely mammalian hormone with a critical role in both birth and lactation, it was an obvious candidate for involvement in maternal behavior. In fact oxytocin has been termed the hormone of mother love (Klopfer, 1971 Newton, 1973). As mentioned above, animal research offers support for this hypothesis (Pedersen, 1996). However, evidence implicating oxytocin in human behavior only recently has begun to accumulate, and direct evidence for a behavioral effect of oxytocin in humans remains to be demonstrated. 

Fleming, A. S., Steiner, M., and Anderson, V. 1987. Hormonal and attitudinal correlates of maternal behavior during the early postpartum period. Journal of Reproductive and Infant Psychology 5 193—205. 

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