Transforming Growth Factors (TGF β) inhibin and activin are involved in the endocrine regulation of pituitary gonadotrophin secretion however the precise implications of this involvement in female diabetic rats is less understood.Virgin female Sprague-Dawley rats aged 6 weeks housed in clear polypropylene cages (43 cm x 30 cm x 15 cm) with laboratory-grade pine shavings as bedding were divided into 3 groups. Control group (n = 28); fed on normal rat pellets. Streptozotocin (STZ) diabetic group (n = 28); received a single IP injection of streptozotocin 45 mg/kg BW (Guneli et al., 2008) in Na+ citrate buffer pH 4.5. Insulin resistant (IR) group (n = 28); fed ad libitum on special diet containing 25% fructose W/W for 12 weeks (Arikawe et al., 2006; Arikawe et al., 2012).Following hyperglycaemia confirmation at 14th weeks of age, estrous cycle was monitored by colpocytological examination daily for 14 consecutive days and animals were sub-grouped based on four phases of the estrous cycle. During each phase, blood samples were collected by cardiac puncture under light anaesthesia (IP, tribromoethanol, 250mg/kg) for serum activin A and inhibin B concentrations using ELISA method. The procedures were performed in accordance with guidelines of the College Ethical Committee on the use of laboratory animals for research. All data are presented as mean ± standard error of mean (SEM). The data was analyzed using Two-way ANOVA (analysis of variance) followed by Tukey’s multiple comparisons test. Level of statistical significance was taken at P < 0.05.The experimental groups exhibited a disordered estrous cycle pattern with prolonged proestrus, metestrus, diestrus phases and a significantly reduced (P < 0.05) estrus phase compared to the control group. Serum inhibin B was significantly lower (P < 0.05) in the experimental groups during all phases of the estrous cycle compared to the control group. Serum activin A was significantly higher (P < 0.05) in the IR group compared to the Control and STZ groups during proestrus and metestrus phases while it was significantly lower (P < 0.05) in the IR group compared to the Control and STZ groups during estrus and diestrus phases of the estrous cycle. The results of the study indicate that diabetes mellitus affect TGF β secretion and open a new prospect to study hormonal profile and hypothalamo-pituitary-ovarian axis in insulin resistant diabetic female rats with a view to identify neuroendocrine centres that might be implicated.