Effect of diabetes mellitus during the luteal phase of the oestrous cycle on preovulatory follicular function, ovulation and gonadotrophins in gilts

Abstract

Development of preovulatory follicles was studied during the oestrous cycle in two experiments designed to examine the effects of short-term lack of insulin on preovulatory follicular function and (Expt 2 only) ovulation. In Expt 1, on day 12 of the third postpubertal oestrous cycle, insulin treatment was discontinued in streptozocin-induced diabetic gilts (n = 4), and on day 18, ovaries were removed from the diabetic gilts and from four normal untreated gilts. Diabetic gilts had a higher percentage of macroscopically atretic follicles (29.4 versus 6.8%; SEM = 5.9, P < 0.03) than did normal gilts. Binding of 125I-labelled hCG by freshly collected granulosa cells from non-atretic follicles was similar in diabetic and normal gilts. Diabetic gilts had more LH peaks in 3 h on days 12-17 of the oestrous cycle than did normal gilts (2.3 versus 1.6; SEM = 0.12; P < 0.01). Serum oestradiol and progesterone concentrations were not affected by treatment, but serum testosterone was increased (P < 0.01) in diabetic gilts. In Expt 2, insulin treatment was withdrawn from nine diabetic gilts on day 12 of the oestrous cycle and ten normal gilts served as controls. On day 18, ovaries were removed from six diabetic and six normal gilts; four normal and three diabetic gilts were ovariectomized 25 days after oestrus. Follicular diameter of diabetic gilts tended to be smaller than that of control (control: 3.95 versus diabetic: 3.01 mm; SEM = 0.4, P < 0.08) and the proportion of follicles with histologic evidence of atresia was higher in diabetic gilts (control: 29 versus diabetic: 47%; SEM = 5; P < 0.05) on day 18. In both experiments, the insulin-like growth factor I (IGF-I) and oestradiol concentrations of follicular fluid of diabetic gilts untreated with insulin from day 12 to day 18 was lower than in nondiabetic gilts. After day 18 in Expt 2, normal gilts exhibited oestrus (duration of cycle was 20 +/- 0.5 days) accompanied by preovulatory surges in oestradiol and LH, whereas diabetic gilts did not exhibit oestrus or ovulate. In diabetic gilts, oestradiol concentrations were lower compared with those of normal gilts, and LH patterns were characterized by two (two gilts) or three (one gilt) increases of more than 2 ng ml-1 between day 18 and day 25. Thus, impaired follicular function in diabetic gilts is not explained by decreased function of the hypothalamo-pituitary axis, since LH was not decreased.(ABSTRACT TRUNCATED AT 400 WORDS)

Anti-diabetic potentials of Momordica charantia and Andrographis paniculata and their effects on estrous cyclicity of alloxan-induced diabetic rats

“…In the same manner, alloxan suppressed luteinizing hormone secretion in female rats (Kinoshita et al, 2004). Additionally, diabetic gilts did not exhibit estrous or ovulation (Cox et al, 1994). Luteinizing hormone surge was also absent in immature alloxan-induced diabetic rats that led to anovulation (Kirchick et al, 1978).…”

“…Specifically, diabetes mellitus suppresses luteinizing hormone secretion in streptozocin-induced diabetic rats (Cagampang et al, 1997) and disrupts estrous cycle (Cox et al, 1994). Estrous cycle is the period of reproductive cyclicity in animals that usually lasts for 4-5 days in rodents (Pineda, 2003).…”

Physiological Changes in Oocyte-Cumulus Cell Complexes from Diabetic Mice that Potentially Influence Meiotic Regulation1

“…Diabetes has been shown to reduce the number of ova ovulated or cause delays in embryonic development [5][6][7][8][9][10][11][12][13]. In an earlier study, we utilized a mouse model of streptozotocin-induced type I diabetes to show that diabetes also adversely affects the process of oocyte maturation [13].…”

Influence of insulin on follicular development and the intrafollicular insulin-like growth factor I (IGF-I) system in sows after weaning

“…Modulation of the IGF-I system via alterations in IGFBPs could also be a method by which insulin influences follicular function. For example, Edwards et al (1996) reported an increase in IGFBP-1 and IGFBP-2 concentrations in diabetic gilts, and this could alter the IGF-I system by affecting (Cox et al, 1987a, b (Cox et al, 1994 (Edwards et al, 1996) (Qiu, 1995) …”