Progesterone physiologic effects

The physiological effects of progesterone are mediated by two progesterone receptor isoforms termed PR-A and PR-E. These arise from a single gene and act as ligand-activated transcription factors to regulate the expression of... 

Although the various steroid hormones have remarkably different physiological effects, their stractures are quite similar. For example, the only difference between testosterone and progesterone is the substituent at C-17, and the only difference between 5a-dihydrotestosterone and estradiol is one carbon and six hydrogens, but these compounds make the difference between being male and being female. These examples illustrate the extreme specificity of biochemical reactions. 

Physiological Effects. The follicular hormone (estrogen) is responsible primarily for the regular course of the genital cycles, which are the estrus cycles (assay procedures on laboratory animals) or the menstrual cycles (in man and monkeys). Estrone causes uterine mucosa to proliferate. During the cycle it acts in conjunction with progesterone and the hypophyseal hormones (cf. also Section 11.)... 

Compared to the greatly differing physiological effects, the chemical differences at first appear minor. But too often one overlooks the fact that the side chains of amino acids are after all quite different. And if one were to compare the complete structural formulas of the peptides, then the differences would indeed appear much greater than they are, for example, among progesterone, corticosterone, and testosterone. 

The ovary also produces inhibin and activin. These peptides consist of several combinations of and 3 subunits and are described in greater detail later. The oc3 dimer (inhibin) inhibits FSH secretion while the 33 dimer (activin) increases FSH secretion. Studies in primates indicate that inhibin has no direct effect on ovarian steroidogenesis but that activin modulates the response to LH and FSH. For example, simultaneous treatment with activin and human FSH enhances FSH stimulation of progesterone synthesis and aromatase activity in granulosa cells. When combined with LH, activin suppressed the LH-induced progesterone response by 50% but markedly enhanced basal and LH-stimulated aromatase activity. Activin may also act as a growth factor in other tissues. The physiologic roles of these modulators are not fully understood. 

Little B, Matta RJ, Zahn TP. Physiological and psychological effects of progesterone in man. J Nerv Ment Dis 1974 159 256-262. 

Vanadate(V) has been shown to block the activation of a progesterone receptor complex from avian oviduct104. Whether this effect involves phosphate metabolism is not known. A possible link between hormonal effects and the metabolism of vanadium in the reproductive physiology of rats has been investigated165"167. ... 

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