Testosterone, dihydrotestosterone, androstenedione and dehydroepiandrosterone concentrations in placentae, ovaries and plasma of the rat in late pregnancy

Abstract

Testosterone (T), dihydrotestosterone (DHT), androstenedione (\g=D\4) and dehydroepiandrosterone (DHA) were measured by radioimmunoassay in peripheral plasma, uterine vein plasma, ovary and placentae within the last 3\p=n-\4days of pregnancy in Sprague-Dawley rats. In the uterine vein, T and \ g=D\ 4 levels were significantly higher than those reported in the peripheral plasma at any particular day of late pregnancy. In peripheral plasma as in uterine vein plasma \ g=D\ 4 and T gradually decreased from day 20 to term (\m=-\63% for \ g=D\ 4 and approximately \m=-\45%for T) whereas DHT concentrations were unchanged. This decline is concomitant with a similar pattern of change in the placentae; indeed placental concentrations of \ g=D\ 4 and T decreased significantly from day 19 to 22 (\m=-\63 and \m=-\79%,respectively) and were positively correlated with the levels of both androgens in uterine venous and peripheral plasma. Thus it was concluded that in the late phase of pregnancy in the rat circulating \ g=D\ 4 and T originate from placentae. In contrast, ovarian androgen concentrations showed a sharp increase from day 21 to term: 58% for DHA, 49% for \ g=D\ 4, 87% for T and 24% for DHT. It is suggested that these increasing concentrations of ovarian androgens could be related to the next ovulatory cycle.In the mid-pregnant rat, recent studies have as¬ signed increasing importance of androgens for maintenance of pregnancy: testosterone (T) is an

Mating Stimuli Influence Endogenous Variations in the Neurosteroids 3α,5α‐THP and 3α‐Diol

“…The present findings are consistent with previous research that has shown endogenous variations in steroids to be a function of reproductive state, and extend them to show central concentrations of the steroids across various brain regions in different endocrine states. Consistent with previous reports, plasma concentrations of progestins ( 43–46) and androgens ( 47–50) increase during pro‐oestrus and pregnancy, and decrease post‐partum and in older rats. The present findings demonstrate that whole brain levels tend to fluctuate in parallel with plasma concentrations of each of the steroids examined.…”

Maternal gestational androgen levels in female marmosets (Callithrix geoffroyi) vary across trimesters but do not vary with the sex ratio of litters

“…The onset of pregnancy in a number of species is also associated with concomitant increases in the production of androgens (dog: Concannon & Castracane, 1985; baboon: Castracane & Goldzieher, 1983; human females: Castracane & Asch, 1995; Castracane et al, 1998; rhesus macaques: Challis et al, 1975; marmoset: Chambers & Hearn, 1978; Fite et al, 2005; rat: Gibori & Sridaran, 1981; Legrand et al, 1984). There is a growing interest in the possibility that maternally-derived androgens can significantly impact embryonic and fetal development in vertebrates (Groothuis et al, 2005; Dloniak et al, 2006; Hines, 2006).…”

Distribution and changes in amounts of the androgen receptor in the pig uterus during the estrous cycle, early pregnancy and after treatment with sex steroids

“…In pigs, androgens have been detected in follicular fluid and corpora lutea (Przala et al 1984, Grant et al 1989, Smith et al 1992, however plasma concentrations of androgens during the porcine estrous cycle have been only partially described. Other sources of androgens such as elongating blastocysts (Fisher et al 1985) and the placenta (Legrand et al 1984) could increase local amounts of androgens and perhaps influence specific physiological processes related to pregnancy.…”