Ss. Lu et al., LACTATE STIMULATES PROGESTERONE SECRETION VIA AN INCREASE IN CAMP PRODUCTION IN EXERCISED FEMALE RATS, American journal of physiology: endocrinology and metabolism, 34(5), 1996, pp. 910-915
The effect-of exercise on the production of ovarian progesterone was e
xamined in female rats. During in vivo experiments, diestrous rats wer
e catheterized via the right jugular vein (RJV), and blood samples wer
e collected before and after 10, 15, 30, and 60 min of swimming. In ad
dition. 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 t
he in vivo condition was performed. The ovarian tissue was challenged
with lactate (0.01-10 mM) or porcine follicle-stimulating hormone (1 m
u g/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 gonadot
ropin-releasing hormone for 30 min. The postexercise levels of plasma
glucose, lactate, and progesterone at 10, 15, and 30 min were signific
antly higher than the corresponding basal levels. Plasma luteinizing h
ormone (LH) did not change after exercise. An elevation of plasma lact
ate and progesterone was found at 15 and 30 min subsequent to 10 min o
f infusion of lactate. Lactate ranging from 0.01 to 10 mM significantl
y increased ovarian adenosine 3',5'-cyclic monophosphate (cAMP) and pr
ogesterone production in a dose-dependent manner. LH concentration in
plasma was not changed subsequent to lactate infusion. LH level in med
ia 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 i
s due directly to a stimulatory effect of lactate on the production of
ovarian cAMP.