Prostaglandins, Leukotrienes and Essential Fatty Acids 75 (2006) 351–355 Restricted diet modifies carbohydrate metabolism in immature rats N. Lanfri-Aguilar a , R. Gallara´ b , J.A. Linares a , L. Campos a , A. Finkelberg a,Ã a Ca´tedra de Fisiologı´a, Facultad de Odontologı´a, Universidad Nacional de Co´rdoba, Co´rdoba, Haya de la Torre S/N—Pabello´n Argentina (Anexo), Ciudad Universitaria—Co¨rdoba, CP 5000, Argentina b Ca´tedra de Quı´mica y Fı´sica Biolo´gicas ‘‘A’’, Facultad de Odontologı´a, Universidad Nacional de Co´rdoba, Co´rdoba, Argentina Received 26 December 2005; received in revised form 8 June 2006; accepted 22 June 2006 Abstract The aim of the present work was to study the effect of a restricted diet on carbohydrate metabolism in submandibular glands of female prepuber rats and the influence of arachidonic acid derivatives. Rats of 21 days of age were divided into three groups. Group I: normally fed rats. Group II: restricted diet (50% of the normal food intake). Group III: normally restricted diet with re-feeding. The baseline concentration of tissue glycogen was significantly higher in Group II than in I or III and after 60 min of incubation in a glucose free medium all groups showed a glycogen drop. In addition, the glucose metabolism was increased in Group II. Cycloxigenase inhibitors failed to alter 14 CO 2 levels in Groups I and III. In Group II, indomethacin and acetylsalicylic acid inhibited glucose metabolism, which was reverted by PGE 2 addition. The exogenous arachidonic acid metabolism and different eicosanoids showed that restricted diet significantly increased the production of PGE 2 but diminished PGF 2a production. Our results suggest that a restricted diet would lead to a new dynamic equilibrium of glucose homeostasis. Prostaglandins E 2 and F 2a would participate by adapting the source of energy to tissue demands while maintaining the metabolic features that characterize puberty. r 2006 Elsevier Ltd. All rights reserved. 1. Introduction The availability of nutrients is one of the most critical factors in the establishment of puberty. If food intake is severely restricted, puberty development is impaired and the onset of fertility is delayed. The effect of malnutri- tion upon development is directly related to the amount [1] as well as to the composition [2] of the diet. Glucose availability will be a key factor in the suppression of LH secretion by fasting since the peripheric input of information seems to be triggered by glucose availability at gastrointestinal level and transmitted by the vagus nerve to the central nervous system [3]. It has been shown that submandibular gland (SMG) plays an active role in repair and permanent recovery of mucogingival tissues as well as in defense mechanisms, thus protecting hard and soft tissues within the oral cavity [4]. Accordingly, SMG from adult rats obtains the necessary energy for secretory activity through glucose metabolism [5]. However, the effects of a restricted diet upon carbohydrate metabolism of salivary glands are somewhat controverted [6,7]. Besides, prostaglandins found in salivary glands, act as functional modulators of both auto and paracrine activities in addition to their role in salivary gland physiology [8]. Keeping in mind these data, the aim of the current work was to assess metabolic changes of glucose in immature rats SMG by means of a diet restriction. Additionally, the possible role of PGE 2 on glucose metabolism of SMG from rats submitted to a 50% restricted diet for 25 days was also explored. 2. Material and methods 2.1. Animals Female Wistar rats (21 days of age) were used. They were individually housed in metabolic cages and kept in ARTICLE IN PRESS www.elsevier.com/locate/plefa 0952-3278/$ - see front matter r 2006 Elsevier Ltd. All rights reserved. doi:10.1016/j.plefa.2006.06.006 Ã Corresponding author. Tel.: +54 3514333033; fax: +54 3514334178. E-mail address: finkelberg1@yahoo.com (A. Finkelberg).