ABSTRACT
AIM: Investigate, in healthy sedentary rats, the potential mechanisms involved on the effects of beta hydroxy beta methylbutyrate (HMB) supplementation upon the glycaemic homeostasis, by evaluating the insulin sensitivity in liver, skeletal muscle, and white adipose tissue. METHODS: Rats were supplemented with either beta hydroxy beta methylbutyrate (320 mg kg(-1) BW) or saline by gavage for 4 weeks. After the experimental period, the animals were subjected to the glucose tolerance test (GTT) and plasma non-esterified fatty acids (NEFA) concentration measurements. The soleus skeletal muscle, liver and white adipose tissue were removed for molecular (western blotting and RT-PCR) and histological analysis. RESULTS: The beta hydroxy beta methylbutyrate supplemented rats presented: (i) higher ratio between the area under the curve (AUC) of insulinaemia and glycaemia during glucose tolerance test; (ii) impairment of insulin sensitivity on liver and soleus skeletal muscle after insulin overload; (iii) reduction of glucose transporter 4 (GLUT 4) total and plasma membrane content on soleus; (iv) increased hormone-sensitive lipase (HSL) mRNA and protein expression on white adipose tissue and plasma NEFA levels and (v) reduction of fibre cross-sectional area of soleus muscle. CONCLUSION: The data altogether indicate that beta hydroxy beta methylbutyrate supplementation impairs insulin sensitivity in healthy sedentary rats, which, in the long-term, could lead to an increased risk of developing type 2 diabetes.
Subject(s)
Dietary Supplements/toxicity , Insulin Resistance/physiology , Muscle, Skeletal/drug effects , Valerates/toxicity , Adipose Tissue/drug effects , Animals , Blotting, Western , Glucose Tolerance Test , Glucose Transporter Type 4/metabolism , Liver/drug effects , Male , Rats , Rats, Wistar , Real-Time Polymerase Chain ReactionABSTRACT
This work succinctly describes the professional and scientific life of Dr. José R. Giglio, one of the most outstanding Brazilian researchers in the field of Toxinology. During his long and successful career, he has made major contributions, especially in elucidating the function, structure, and mechanisms of action of animal venom proteins (from snakes, scorpions and spiders) as well as the characterization of antibodies and several inhibitors of venoms and toxins. We present here a brief history of Dr. Giglios personal and professional life, also reporting some of his numerous published scientific articles on venoms from snakes (Bothrops, Crotalus, and other genera), scorpions (Tityus sp), spiders (Phoneutria sp), their isolated toxins and natural inhibitors. Thus, this work is a tribute to Dr. Giglio in his 73rd birthday, having devoted 48 years of his life studying animal venoms, an effort that has continued even after his formal retirement from university duties.
