Abstract
Introduction
Fenugreek (Trigonella foenum graecum), a medicinal herb with potent antihyperglycaemic and hypoglycaemic effects, is used
to treat diabetes. This study is aimed to explore the interaction of fenugreek seed
extract (FSE) and HPT (hypothalamic-pituitary-thyroid) axis in context of leptin secretion
which have important role in normal and type-1 diabetic subjects.
Materials and Methods
FSE (confirmed to contain trigonelline, diosgenin, 4 hydroxyisoleucine) was gavaged
(0.25 gm/kg body weight/day) to normal and alloxan-induced type-1 diabetic rats for
4 weeks. Expression of hypothalamic prepro-TRH (Thyrotropin releasing hormone) mRNA,
serum levels of TRH, TSH (Thyroid stimulating hormone), fT3, fT4, insulin, leptin, glucose; thyroperoxidase activity and growth of thyroid gland,
food intake, adiposity index were also studied
Results
FSE significantly down regulated prepro-TRH mRNA expression; decreased serum TRH,
TSH, fT3, fT4 levels, and regressed thyroid gland in FSE-fed normal and diabetic rats than those
observed in normal diet-fed control and diabetic rats. FSE decreased (p<0.005–0.001)
adiposity index and leptin secretion, increased food intake and body weight in all
FSE-fed rats.
Conclusion
FSE improved insulin secretion, decreased glucose level but impaired HPT axis in diabetic
rats, indicating insulin-independent central hypothyroidism. Results suggested that
the dominant signal to hypothalamus suppressing HPT axis is the fall in leptin level
which i resulted from decreased adiposity index following FSE feeding. Fenugreek simultaneously
having hypoglycaemic and hypothyroidal actions raises questions whether it can be
safely used to treat diabetes and/or hyperthyroidism as was suggested by many workers.
Key words
diabetes - fenugreek seed extract - hypoglycaemia - hypothyroidsm and HPT-axis - leptin
