Lactate stimulates progesterone secretion via an increase in cAMP production in exercised female rats

Abstract

The effect of exercise on the production of ovarian progesterone was examined in female rats. During in vivo experiments, diestrous rats were catheterized via the right jugular vein (RJV), and blood samples were collected before and after 10, 15, 30, and 60 min of swimming. In addition, blood samples were collected from the RJV before and 2, 5, 10, 15, 30, 60, and 120 min after 10 min of infusion of lactate (13 mg.kg-1.min-1) through the left femoral vein. To explore if lactate modulates progesterone secretion by acting directly on rat ovary or on anterior pituitary gland (AP), an in vitro experiment that mimicked the in vivo condition was performed. The ovarian tissue was challenged with lactate (0.01-10 mM) or porcine follicle-stimulating hormone (1 microgram/ml) and 3-isobutyl-1-methylxanthine (1 mM) for 60 min, and the AP was challenged with lactate ranging from 0.1 to 10 mM or 10 nM gonadotropin-releasing hormone for 30 min. The postexercise levels of plasma glucose, lactate, and progesterone at 10, 15, and 30 min were significantly higher than the corresponding basal levels. Plasma luteinizing hormone (LH) did not change after exercise. An elevation of plasma lactate and progesterone was found at 15 and 30 min subsequent to 10 min of infusion of lactate. Lactate ranging from 0.01 to 10 mM significantly increased ovarian adenosine 3',5'-cyclic monophosphate (cAMP) and progesterone production in a dose-dependent manner. LH concentration in plasma was not changed subsequent to lactate infusion. LH level in media samples was not altered after incubation of AP with lactate. These results suggest that the increase of plasma progesterone level in rats during exercise is independent of LH secretion and at least in part is due directly to a stimulatory effect of lactate on the production of ovarian cAMP.

Lindane, a gap junction blocker, suppresses FSH and transforming growth factor β1-induced connexin43 gap junction formation and steroidogenesis in rat granulosa cells

“…Progesterone antibody was produced and characterized as previously described (Lu et al 1996). The sensitivity of the assay was 5 pg per well, and the intra-and inter-assay coefficients of variation were 4·0% (n=3) and 7·8% (n=3) respectively.…”

Inhibitory effect of digoxin on testosterone secretion through mechanisms involving decreases of cyclic AMP production and cytochrome P450scc activity in rat testicular interstitial cells

“…The concentrations of cyclic AMP were determined by RIA as described elsewhere (Tsai et al, 1996b;Lu et al, 1996). With anti-cyclic AMP serum No.…”

Estrogen rapidly modulates mustard oil-induced visceral hypersensitivity in conscious female rats: a role of CREB phosphorylation in spinal dorsal horn neurons

“…Estrogen and progesterone plasma levels after a single injection of either sex hormone were determined in two OVX rat groups (n ϭ 5 in each) at 1.5 h, 4 h, 24 h, 48 h, and 5 days. Plasma concentrations of estradiol and progesterone were measured by radioimmunoassay (RIA), as described previously (27,31). With antiestradiol serum no.…”