Ovarian effects of a high lactose diet in the female rat

Abstract

-Young women with galactosemia experience ovarian failure at a very early age raising concern about the ovarian toxicity of galactose. While galactose may be present in the diet as a monosaccharide, it is predominantly derived from cleavage of the disaccharide lactose within the intestine. Our previous studies in animals have shown that high galactose diets inhibit ovarian follicular development and long-term exposure to high lactose diets retards growth of rats. The objective of the present study was to determine whether galactose exposure in the form of dietary lactose mimics the effects found previously with diets rich in galactose. Sixty female Long-Evans rats (25-day-old) were randomly assigned to two groups and fed a control diet (41.9% glucose in AIN93G [American Institute of Nutrition], CON) before lactose treatment. Unilateral ovariectomy (uOVX) was performed on half of the rats in each group to determine baseline ovarian follicle numbers. The study diet was a high lactose diet (HLD) containing 41.9% lactose in AIN93G. Study diet exposure started 1 month after uOVX (3 months old) and continued for 7 months in the treatment group. The control group remained on the 41.9% glucose diet throughout. Vaginal cytology, ovarian morphometric analyses, and serum concentrations of estradiol and progesterone were examined. Long-term exposure to the HLD decreased the body weights of animals and progesterone concentrations in the serum but produced no harmful effects on ovarian morphology or function. Beginning at 5 months of age (two months of lactose treatment) increasing numbers of females began to cycle irregularly but there was no difference between the glucose and lactose diet groups. These negative findings imply that administration of galactose in the form of lactose seems to be much less toxic than when galactose is fed to animals. From a human health perspective, these results are somewhat reassuring, since in general, women eat lactose-containing foods rather than foods that contain large amounts of free galactose.lactose / galactose / ovary / toxicology / rat

Dairy Food Intake Is Associated with Reproductive Hormones and Sporadic Anovulation among Healthy Premenopausal Women

“…An animal study found significantly lower concentrations of estradiol and elevated FSH and LH concentrations in rats fed high amounts of galactose, a breakdown component of lactose, compared with controls (14). In addition, progesterone concentrations were significantly decreased in rats after lactose treatment, whereas no differences were found in serum concentrations of estradiol (13). Here, we did not detect any associations between dairy food intake and lactose and progesterone, but our overall results imply modest changes in reproductive hormones, particularly estradiol and LH, with higher consumption of these foods.…”

“…The biological mechanisms that support an association between dairy food intake and ovulatory function are largely unknown. However, impaired ovarian function was observed in rats fed excessive amounts of lactose (13) and galactose (14), which points to potential biological pathways. These results highlight the need for further study of dairy food intake and reproductive function, particularly among healthy women.…”

Changes of Cyclic AMP Levels and Phosphodiesterase Activities in the Rat Ovary

“…PDE4 is a member of the PDE superfamily that has been identified in ovarian granulosa cells and purposed to play a role in regulation of gonadotropin action [32]. However, cAMP-PDE activity in ovarian follicles is mainly related to PDE3, which is present in oocytes [29,[33][34][35]. Together, they may lead to an increase in PDE activity in ovaries treated with eCG, but the increase is not significant.…”

The Characterization of Obese Polycystic Ovary Syndrome Rat Model Suitable for Exercise Intervention

“…Serial sections were mounted on 3 slides, deparaffinized with xylene, hydrated with successive decreasing concentrations of ethanolin water, and then stained with hematoxylin and eosin (HE). The section with the largest area was chosen for analysis to count the numbers of preantral, antral and atretic follicles, and corporalutea [24]. Atretic follicles were confirmed when one of the following characteristics was observed, such as the presence of pyknosis in the granulose cell, granulosa cells present in the follicular fluid, or theca cell hypertrophy.…”