Progesterone action

NEUROENDOCRINE ACTIONS Progesterone produced in the luteal phase of the cycle decreases the frequency of GuRH pulses, which is one mechanism of action of progestin-containing contraceptives. 

Steroid Hormones and Neurosteroids. Steroids (qv) can affect neuroendocrine function, stress responses, and behavioral sexual dimorphism (78,79) (see Steroids). Mineralocorticoid, glucocorticoid, androgen, estrogen, and progesterone receptors are localized in the brain and spinal cord. In addition to genomic actions, the neurosteroid can act more acutely to modulate the actions of other receptors or ion channels (80). Pregnenolone [145-13-17, ( ) dehydroepiandosterone [53-43-0] C H2 02 (319) are excitatory neurosteroids found in rat brain, independent of adrenal... 

As under most circumstances progesterone action will hold primacy over estrogenic effects, the cervical mucus, endometrium, and probably the fallopian tubes reflect progestational stimulation. The cervical mucus becomes thick and viscous and thus impervious to spermatozoa. The endometrium is in a state that is not receptive for implantation of a fertilized egg. Probably, the progestational impact on the secretory activity and peristalsis in the fallopian tubes also assists the general contraceptive effect. It is difficult, however, to assess the relative contribution of the various effects to the... 

Progesterone produces direct membrane effects [16]. These include actions that promote maturation of spermatozoa as well as oocytes and facilitation of the release of neurotransmitters such as dopamine and LH-releasing hormone (LHRH) (Fig. 52-7). Membrane actions of progesterone also activate oxytocin receptors in the hypothalamus in a way that enables oxytocin to turn on sexual behavior in the estrogen-primed female rat [3],... 

None of these findings undermines the importance of the intracellular genomic actions of steroids. Rather, they increase the richness of the cellular actions of steroid hormones and raise the possibility that there may be connections between genomic and nongenomic actions of steroids. For example, genomic action may induce receptors that mediate nongenomic effects. Moreover, the activation of oxytocin receptors by progesterone is dependent... 

Like steroid hormones, thyroid hormones interact with receptors to alter genomic activity and affect the synthesis of specific proteins during development [25-28], As with testosterone and progesterone, metabolic transformation of thyroxine (T4) is critical to its action [25-28]. Moreover, as with steroid hormones, thyroid hormones alter brain functions in adult life in ways that both resemble and differ from their action during development [25-28]. 

Edwards DP, Altaman M, DeMarzo A, Zhang Y, Weigel N, Beck CA (1995) Progesterone receptor and the mechanism of action of progesterone antagonists. J Steroid Biochem Mol Biol 53 449... 

Segal and Blair (S13) have shown that aldehydes reduce NAD to NADH2 in the presence of aldehyde dehydrogenase progesterone, menthol, and menthone inhibit this enzyme and this may account for the stimulatory action shown by these substances on galactose metabolism in vitro. 

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